The present invention relates to the field of drilling in the ground, in particular in order to construct foundations, e.g. such as continuous screens constituted by juxtaposed concrete wall elements.
The invention relates more precisely to a drilling machine for excavating in ground, and more particularly in hard soil.
The invention relates more precisely to a drilling machine for making an excavation in ground in a drilling direction, said excavation having walls and said drilling machine comprising:
an anchor module having at least an anchor device for preventing the anchor module from moving in the drilling direction relative to the ground by bearing against one of the walls of the excavation;
a drilling anchor module provided with cutter members, the cutter members being movable in translation relative to the anchor module; and
movement means for moving the cutter members in translation relative to the anchor module.
Such a machine is described in particular in Document FR 2 806 112. It comprises anchor means that make it possible to prevent the main frame from moving in the vertical drilling direction relative to the walls of the trench, and means for exerting downwardly-directed vertical thrust on the milling assembly.
Such a machine makes it possible to exert vertical thrust on the cutter members of magnitude that is much greater than the weight of the frame, thus making it possible to drill in hard soil, such as for example granite.
A drawback with that machine is that the cutter members may tend to slip on portions of hard ground, running the risk of causing the path of the drilling machine to be deflected, and this becomes problematic, in particular when drilling to great depth.